Posted
by
Zonk
on Wednesday January 17, 2007 @06:10AM
from the stupid-yellow-orb dept.

If, back in the day, you ever wondered why your old Super Nintendo tended to discolor, your curiosity will now be sated. Via Ars Technica's Opposable Thumbs blog, an article on the Vintage Computing and Gaming site which explains the mysteries of plastic discoloration. From the article: "Since ... different batches of plastics had ... different aging results ... then there must have been a difference of additives between them. Perhaps in one of the production runs of plastic, they didn't get the catalyst or flame retardant mixture quite right and more residues were left over in the top half's plastic batch, thus causing it to degrade more rapidly over time. And by the time Nintendo produced the later runs of Super Nintendos, they had perfected the manufacturing process of their plastic, meaning that those later models aren't as susceptible to oxidation as the earlier models are."

Besides, how does black plastic fade to yellow? I'd think it would turn something more akin to purple.

Why would you think that?

The yellowing method varies between materials, but in plastics, it generally has to do with extra bonds forming between the carbons. PVC, for example, is prone to photoyellowing due to dehydrochlorination -- basically, UV splits off an HCl, thus causing the carbons to crosslink. In fact, a number of plastics are prone to UV photoyellowing -- I wonder if where you kept your SNES he

We have a bunch of CRT monitors that are much more yellow than others, but in a pattern that suggests its from a cleaning agent someone used. (All the ones in one room, only on the visible easily accessible portions) My best guess is the plastic doesnt like ammonia-based stuff like windex.

Yeah, my SNES that I got in 1991 is still its normal color (or fairly close to it anyway. Just the normal dirt or whatnot that one would expect).Not that one example disproves the "Earlier ones turned yellow, later ones didn't" idea in the summary, but, for whatever it's worth, mine didn't anyway.

My SNES is still grey, even though I'm pretty sure it's an early version. The thing that boggles me is, who are these people that are both playing lots of video games and being exposed to sunlight such that the plastic has a chance to fade? Mine never faded because it was either in the basement, or in the living room with the drapes pulled, like any real child-geek should be!

You get the same with a huge number of materials; the problem is that the additives don't complement each other well: if you want flame retardant, you get something that oxidises with light more easily. If you want super-white white, then the damn thing melts if vaguely near a flame. I had to do some research on this about a year ago - it's even worse with fabrics. I think there may be more expensive materials that balance the two better - but then you add expense to the case. You can have superwhite and then top it off with a layer of something tough and clear, but then you need to bind the two materials and create extra manufacturing cost from having thinner slices and having to put them together. Or - like the current trend - you can pick a colour that's not such a pain in the ass.

Man, that must have been one of the REALLY original units, where they didn't get the plastic mix right at all. I got one of the later ones, nice beige-ish color.hehehe Seriously, though, I have had a number of my brown 64 units turn various colors as well. Some darker, some lighter (I actually like the milk-chocolate color, really light brown,) and one turned like an ashy-greyish color. Weird stuff, this plastic.

It really does suck when you have a 128D with a metal case... the paint on the case does not

Yes, my mac-plus (platinum gray) turned yellow except for the base which was flat against a foam block in the case it was in. Now it looks like a first-gen mac-plus. Mouse turned too. I have an old imagewriter printer though - it's still white.

The SNES turning yellow was a huge technological leap for Nintendo.My old NES just decomposed - I kept it in the attic for a couple of years, but the day i went up there to get it, there was nothing nothing left but a pile of dirt. The only thing unaffected by the decay was the golden finish on my Zelda 2 cartridge.

Read the article. It's not cigarette smoke; no-one in my family smoked, and my computer actually yellowed more after it was packed away. Similarly, the floppy disk drive which appeared identical and was exposed to near-identical conditions hasn't yellowed.

I only said smoking because anyone who has ever seen the walls and ceiling of an apartment where a heavy smoker has lived for a longer period of time should know what smoke does to white or bright surfaces over long periods of time.

I noticed a while back that (amongst other things) my Atari 800XL [smithore.com] (not my photo) had yellowed badly, but that the 1050 disk drive [zock.com] (again, not mine), which was part of the same bundle and appeared to use the same beige plastic still looked "as new". I doubt varying exposure to daylight could account for all of this.

Can't say without seeing it, but are you sure it's fading, or is it just tiny particles of loose skin and grease embedded where you're resting your wrists? The same thing happened to my wrist-rest... (eww..)

It appears the coating (electroplating?) is fading. My fiance was given an old temporary Acer TM and some parts that used to be the grey finish were a sort of faint green/lime colour.. so go figure.
My next notebook is most likely going to be an IBM anyway.

IBMs do it too. I had an A22m before my current Inspiron E1505, and by the time I got rid of it the texturing on the plastic of the hand grooves had worn smooth. (Shiny, too.) Same thing's happening with the shoddy silver plastic on my E1505.

IBMs just go shiny, the plastic is actually black through and through. Some of the surfaces on some IBMs are made of metal and painted black, like the underneath, in which case you see the metal if you scratch the paint off.A lot of cheaper laptops (experience with fujitsu and dell) which are silver coloured, are just painted silver and have very ugly white plastic underneath... They look awfull when you wear through the paint.

The same thing happened to SNES cartidges. They were made out of two pieces of plastic that clipped together. Many of my older cartidges have one yellow half and one half that still looks normal, propbably because they were made out of two different batches of the plastic.

I never got to see my SNES turn yellow because I painted it red and black (controllers also) and drew a crude iguana on it. I had to do it because there were a lot of Nintendos getting stolen back then. I had to make mine stand out.

The article mentions sunlight as a culprit.While I stayed in smaller accommodation for a year and a bit, I did the sensible thing and packed all my model planes away in their original packaging - clear plastic tray with a clear plastic lid, inside a thick cardboard box, in a cupboard that no sunlight was getting into. When I came to unpack them, I discovered that the tails of two planes had yellowed - as had the clear plastic in their boxes. Definitely not sunlight in that case; you'd think the manufacturer

The article clearly mentions that sunlight is only one possible cause for a certain type of plastic with certain additives.

Simple exposure to oxygen or heat can cause yellowing too over time. And in your case, it's possible that the clear plastic packaging degraded and outgassed nasty chemicals that could have accelerated the aging of your plane.

I have a mouse at work I brought from home, and about 60% of the silver paint has worn off. It worn off right where my palm & fingers touch it. There's a small spot underneath the big button where my thumb touches, totally dull gray.

Nothing ages as badly as keyboards and mice. Not only do they get that yellow aging funk described in the article but they also have your bacteria, skin oil, worn keys, coffee spills, crumbs, etc. After 5 years they start to resemble archeological artifacts. Get an old keyboard that was used by a guy with a beard and you'll really cringe.